diff --git a/ftplugin/http.lua b/ftplugin/http.lua
index 49da4da..23b5c02 100644
--- a/ftplugin/http.lua
+++ b/ftplugin/http.lua
@@ -1,4 +1,7 @@
 vim.bo.commentstring = "# %s"
 vim.wo.conceallevel = 0
 
+local dotenv = require("rest-nvim.dotenv")
+
 vim.b._rest_nvim_count = 1
+vim.b._rest_nvim_env_file = dotenv.find_relevent_env_file()
diff --git a/lua/rest-nvim/dotenv.lua b/lua/rest-nvim/dotenv.lua
index 8e58678..81113a4 100644
--- a/lua/rest-nvim/dotenv.lua
+++ b/lua/rest-nvim/dotenv.lua
@@ -71,6 +71,35 @@ function M.find_env_files()
   return files
 end
 
+---@return string? dotenv file
+function M.find_relevent_env_file()
+  local filename = vim.fn.expand("%:t:r")
+  if filename == "" then
+    return nil
+  end
+  filename = filename:gsub("%.http$", "")
+  ---@type string?
+  local env_file
+  -- search for `/same/path/filename.env`
+  env_file = vim.fs.find(filename .. ".env", { type = "file" })[1]
+  if env_file then
+    return env_file
+  end
+  -- search upward for `.env` file
+  env_file = vim.fs.find(function (name, _)
+    return name == ".env"
+  end, {
+    path = vim.fn.expand("%:h"),
+    upward = true,
+    stop = vim.fn.getcwd(),
+    type = "file",
+    limit = math.huge,
+  })[1]
+  if env_file then
+    return env_file
+  end
+end
+
 ---@param bufnr number? buffer identifier, default to current buffer
 ---@return string? path
 function M.select_file(bufnr)
diff --git a/spec/dotenv_spec.lua b/spec/dotenv_spec.lua
new file mode 100644
index 0000000..d1588e0
--- /dev/null
+++ b/spec/dotenv_spec.lua
@@ -0,0 +1,33 @@
+---@module 'luassert'
+
+require("spec.minimum_init")
+
+local dotenv = require("rest-nvim.dotenv")
+
+local function open(path)
+  vim.cmd.edit(path)
+  vim.cmd.source("ftplugin/http.lua")
+  return 0
+end
+
+local function remove_cwd(path)
+  path = path:gsub(vim.pesc(vim.fn.getcwd()) .. "/", "")
+  return path
+end
+
+describe("dotenv", function ()
+  it("find dotenv file with same name to http file", function ()
+    open("spec/examples/dotenv/with_dotenv.http")
+    assert.same(
+      "spec/examples/dotenv/with_dotenv.env",
+      remove_cwd(vim.b._rest_nvim_env_file)
+    )
+  end)
+  it("find dotenv file in parent dir", function ()
+    open("spec/examples/dotenv/without_dotenv.http")
+    assert.same(
+      "spec/examples/.env",
+      remove_cwd(vim.b._rest_nvim_env_file)
+    )
+  end)
+end)
diff --git a/spec/examples/.env b/spec/examples/.env
new file mode 100644
index 0000000..657866e
--- /dev/null
+++ b/spec/examples/.env
@@ -0,0 +1 @@
+# dotenv file for `example/dotenv/without_dotenv.http` example
diff --git a/spec/examples/dotenv/deeper_path/.env b/spec/examples/dotenv/deeper_path/.env
new file mode 100644
index 0000000..e69de29
diff --git a/spec/examples/dotenv/deeper_path/with_dotenv.env b/spec/examples/dotenv/deeper_path/with_dotenv.env
new file mode 100644
index 0000000..e69de29
diff --git a/spec/examples/dotenv/with_dotenv.env b/spec/examples/dotenv/with_dotenv.env
new file mode 100644
index 0000000..e69de29
diff --git a/spec/examples/dotenv/with_dotenv.http b/spec/examples/dotenv/with_dotenv.http
new file mode 100644
index 0000000..e69de29
diff --git a/spec/examples/dotenv/without_dotenv.http b/spec/examples/dotenv/without_dotenv.http
new file mode 100644
index 0000000..e69de29